/*******************************************************************************
 * Copyright (c) 2006 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Actuate Corporation  - initial API and implementation
 *******************************************************************************/

package org.eclipse.birt.chart.render;

import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.eclipse.birt.chart.computation.DataPointHints;
import org.eclipse.birt.chart.computation.GObjectFactory;
import org.eclipse.birt.chart.computation.IGObjectFactory;
import org.eclipse.birt.chart.datafeed.DifferenceEntry;
import org.eclipse.birt.chart.device.IPrimitiveRenderer;
import org.eclipse.birt.chart.event.EventObjectCache;
import org.eclipse.birt.chart.event.LineRenderEvent;
import org.eclipse.birt.chart.event.PolygonRenderEvent;
import org.eclipse.birt.chart.event.StructureSource;
import org.eclipse.birt.chart.exception.ChartException;
import org.eclipse.birt.chart.model.ChartWithAxes;
import org.eclipse.birt.chart.model.attribute.ColorDefinition;
import org.eclipse.birt.chart.model.attribute.Fill;
import org.eclipse.birt.chart.model.attribute.Gradient;
import org.eclipse.birt.chart.model.attribute.LineAttributes;
import org.eclipse.birt.chart.model.attribute.Location;
import org.eclipse.birt.chart.model.attribute.MultipleFill;
import org.eclipse.birt.chart.model.component.Series;
import org.eclipse.birt.chart.model.data.SeriesDefinition;
import org.eclipse.birt.chart.model.type.LineSeries;
import org.eclipse.birt.chart.util.ChartUtil;
import org.eclipse.birt.chart.util.FillUtil;
import org.eclipse.emf.common.util.EList;

/**
 * Renderer utility for difference chart
 */

public final class DifferenceRenderer
{

	protected static final IGObjectFactory goFactory = GObjectFactory.instance( );

	final static double kError = 0.5d;

	/**
	 * 
	 * Stands for a part of line with the start point and end point
	 * 
	 */
	static class CLine
	{

		public transient CPoint start;
		public transient CPoint end;

		/**
		 * Constructor
		 * 
		 * @param start
		 *            start point of line
		 * @param end
		 *            end point of line
		 * @param bTransposed
		 */
		public CLine( CPoint start, CPoint end )
		{
			this.start = start;
			this.end = end;
		}

		public double getSlope( )
		{
			if ( isVertical( ) )
			{
				return Double.NaN;
			}
			return ( end.y - start.y ) / ( end.x - start.x );
		}

		public boolean isVertical( )
		{
			return CPoint.bPrecise ? start.x == end.x
					: ChartUtil.mathEqual( start.x, end.x );
		}

		/**
		 * Checks the point is not out of bound. Needs to ensure the point is in
		 * the Line, otherwise it's useless.
		 * 
		 * @param point
		 *            point, usually used as an intersection point
		 * @return if the point is in the bound of line
		 */
		boolean checkBoundOfPoint( CPoint point )
		{
			boolean b;
			// To use non-precise checking policy to ensure the intersection
			// point won't be ignored

			// if ( CPoint.bPrecise )
			// {
			// b = start.x < end.x ? point.x >= start.x && point.x <= end.x
			// : point.x <= start.x && point.x >= end.x;
			// // if ( b )
			// // {
			// // b = start.y < end.y ? point.y >= start.y
			// // && point.y <= end.y : point.y <= start.y
			// // && point.y >= end.y;
			// // }
			// }
			// else
			{
				// Only check one attribute since two lines should be both
				// checked
				b = ChartUtil.mathLT( start.x, end.x )
						? ChartUtil.mathGE( point.x, start.x )
								&& ChartUtil.mathLE( point.x, end.x )
						: ChartUtil.mathLE( point.x, start.x )
								&& ChartUtil.mathGE( point.x, end.x );
			}
			return b;
		}

		/**
		 * Finds intersection point of two lines
		 * 
		 * @param line
		 *            other line to intersect
		 * @return the intersection point or null
		 */
		public CPoint findIntersection( CLine line )
		{
			if ( this.isVertical( ) || line.isVertical( ) )
			{
				return null;
			}

			final double k1 = this.getSlope( );
			final double k2 = line.getSlope( );
			if ( k1 == k2 )
			{
				if ( this.end.equals( line.start ) )
				{
					return this.end;
				}
				else if ( this.start.equals( line.end ) )
				{
					return this.start;
				}
				return null;
			}

			double pointX = ( line.start.y - this.start.y + k1 * this.start.x - k2
					* line.start.x )
					/ ( k1 - k2 );
			double pointY = k1 * ( pointX - this.start.x ) + this.start.y;
			CPoint intersection = null;
			if ( this.start.bTransposed )
			{
				intersection = new CPoint( pointY,
						pointX,
						this.start.bTransposed );
			}
			else
			{
				intersection = new CPoint( pointX,
						pointY,
						this.start.bTransposed );
			}
			if ( !this.checkBoundOfPoint( intersection )
					&& !line.checkBoundOfPoint( intersection ) )
			{
				return null;
			}
			// boolean b1 = this.checkBoundOfPoint( intersection );
			// boolean b2 = line.checkBoundOfPoint( intersection );
			// if ( b1 )
			// {
			// System.out.println( "b2:" + b2 + intersection );
			// System.out.println( this );
			// System.out.println( line );
			// }
			// if ( b2 )
			// {
			// System.out.println( "b1:" + b1 + intersection );
			// System.out.println( this );
			// System.out.println( line );
			// }
			// if ( !b1 && !b2 )
			// // || intersection.y == this.start.y
			// // || intersection.y == line.start.y )
			// {
			// return null;
			// }
			return intersection;
		}

		@Override
		public String toString( )
		{
			return "Start point:" + start + " End point:" + end; //$NON-NLS-1$ //$NON-NLS-2$
		}
	}

	static class CPointContainer
	{

		private final HashSet<String> set = new HashSet<String>( );
		private final LinkedList<CPoint> list = new LinkedList<CPoint>( );

		public int size( )
		{
			return list.size( );
		}

		public void clear( )
		{
			set.clear( );
			list.clear( );
		}

		public boolean contains( CPoint o )
		{
			return set.contains( o.toString( ) );
		}

		public void add( CPoint o )
		{
			set.add( o.toString( ) );
			list.add( o );
		}

		public void addFirst( CPoint o )
		{
			set.add( o.toString( ) );
			list.addFirst( o );
		}

		public List<CPoint> getPoints( )
		{
			return list;
		}
	}

	static class CPoint
	{

		/**
		 * Main coordinate. If transposed, the value is Y coordinate.
		 */
		public transient double x;

		/**
		 * Sub coordinate. If transposed, the value is X coordinate.
		 */
		public transient double y;
		public transient boolean bTransposed = false;

		public static transient boolean bPrecise = false;

		public CPoint( double x, double y, boolean bTransposed )
		{
			this.bTransposed = bTransposed;
			if ( bTransposed )
			{
				this.y = x;
				this.x = y;
			}
			else
			{
				this.x = x;
				this.y = y;
			}
		}

		public CPoint( double[] point, double offset, boolean bTransposed )
		{
			this( point[0] + offset, point[1] + offset, bTransposed );
		}

		public Location toLocation( )
		{
			return bTransposed ? goFactory.createLocation( y, x )
					: goFactory.createLocation( x, y );
		}

		public void addToListBottom( CPointContainer points )
		{
			if ( !points.contains( this ) )
			{
				points.addFirst( this );
			}
		}

		public void addToList( CPointContainer points )
		{
			if ( !points.contains( this ) )
			{
				points.add( this );
			}
		}
		
		@Override
		public String toString( )
		{
			return "b=" + bTransposed + " x=" + ChartUtil.formatDouble( x ) + " y=" + ChartUtil.formatDouble( y ); //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
		}

		@Override
		public boolean equals( Object obj )
		{
			if ( this == obj )
			{
				return true;
			}
			if ( obj instanceof CPoint )
			{
				CPoint p = (CPoint) obj;
				if ( bPrecise )
				{
					return this.x == p.x
							&& this.y == p.y
							&& this.bTransposed == p.bTransposed;
				}
				return ChartUtil.mathEqual( this.x, p.x )
						&& ChartUtil.mathEqual( this.y, p.y )
						&& this.bTransposed == p.bTransposed;
			}
			return false;
		}

		/**
		 * Compares X coordinate of two points
		 * 
		 * @param p
		 *            other point
		 * @return the positive number when current point is located right or
		 *         above
		 */
		public double compareX( CPoint p )
		{
			return bTransposed ? p.x - this.x : this.x - p.x;
		}

		/**
		 * Compares Y coordinate of two points
		 * 
		 * @param p
		 *            other point
		 * @return the positive number when current point is located right or
		 *         above
		 */
		public double compareY( CPoint p )
		{
			return bTransposed ? this.y - p.y : p.y - this.y;
		}
	}

	/**
	 * Creates fills for difference chart
	 * 
	 * @param paletteEntry
	 *            fill from palette
	 * @param isColor
	 *            to determine output fill is ColorDefinition instance if
	 *            possible
	 * @return Fill array
	 */
	public static Fill[] createDifferenceFillFromPalette( Fill paletteEntry,
			boolean isColor )
	{
		Fill fillColorP = null;
		Fill fillColorN = null;
		if ( paletteEntry instanceof ColorDefinition )
		{
			fillColorP = goFactory.copyOf( (ColorDefinition) paletteEntry );
			fillColorN = goFactory.copyOf( (ColorDefinition) paletteEntry );
		}
		else if ( paletteEntry instanceof MultipleFill )
		{
			EList<Fill> fills = ( (MultipleFill) paletteEntry ).getFills( );
			// Copy instance to avoid the element been removed from
			// EObjectContainmentList
			fillColorP = goFactory.copyOf( (ColorDefinition) fills.get( 0 ) );
			fillColorN = goFactory.copyOf( (ColorDefinition) fills.get( 1 ) );
		}
		else if ( isColor && paletteEntry instanceof Gradient )
		{
			fillColorP = goFactory.copyOf( ( (Gradient) paletteEntry ).getStartColor( ) );
			fillColorN = goFactory.copyOf( ( (Gradient) paletteEntry ).getEndColor( ) );
		}
		else
		{
			// Not clone since image or gradient can't be changed directly
			fillColorP = paletteEntry;
			fillColorN = paletteEntry;
		}
		return new Fill[]{
				fillColorP, fillColorN
		};
	}

	private static Fill[] createUpdateFills( AxesRenderer renderer,
			Fill paletteEntry )
	{
		final Fill seriesPalette = getSeriesPaletteEntry( renderer );
		if ( seriesPalette != null )
		{
			paletteEntry = seriesPalette;
		}

		Fill[] fills = createDifferenceFillFromPalette( paletteEntry, false );

		if ( paletteEntry instanceof ColorDefinition )
		{
			if ( renderer.getSeries( ).isSetTranslucent( )
					&& renderer.getSeries( ).isTranslucent( ) )
			{
				fills[0] = goFactory.translucent( (ColorDefinition) paletteEntry );
			}
			else
			{
				fills[0] = goFactory.copyOf( (ColorDefinition) paletteEntry );
			}
			fills[1] = goFactory.copyOf( (ColorDefinition) paletteEntry );
		}
		return fills;
	}

	public static void renderDifferencePolygon( AxesRenderer renderer,
			IPrimitiveRenderer ipr, DataPointHints[] dpha, Location[] loaP,
			Location[] loaN, LineAttributes liaP, LineAttributes liaN,
			Fill paletteEntry ) throws ChartException
	{
		CPoint.bPrecise = false;

		if ( loaP == null || loaN == null || loaP.length < 2 || loaN.length < 2 )
		{
			return;
		}

		final boolean isTransposed = ( (ChartWithAxes) renderer.getModel( ) ).isTransposed( );
		final LineRenderEvent lre = ( (EventObjectCache) ipr ).getEventObject( StructureSource.createSeries( renderer.getSeries( ) ),
				LineRenderEvent.class );
		final PolygonRenderEvent pre = ( (EventObjectCache) ipr ).getEventObject( StructureSource.createSeries( renderer.getSeries( ) ),
				PolygonRenderEvent.class );
		final DeferredCache dc = renderer.getDeferredCache( );

		int findex = getFirstNonNullIndex( dpha );
		int lindex = getLastNonNullIndex( dpha );

		if ( findex < 0 || lindex < 0 )
		{
			// Returns since no valid entry
			return;
		}

		final Fill[] fills = createUpdateFills( renderer, paletteEntry );
		final Fill fillColorP = fills[0];
		final Fill fillColorN = fills[1];

		// Points to render polygon
		CPointContainer points = new CPointContainer( );

		CPoint pStart = new CPoint( loaP[findex].getX( ),
				loaP[findex].getY( ),
				isTransposed );
		CPoint nStart = new CPoint( loaN[findex].getX( ),
				loaN[findex].getY( ),
				isTransposed );
		CPoint pEnd, nEnd;

		for ( int i = findex + 1; i <= lindex; i++ )
		{
			if ( !isValidDifferenceEntry( dpha[i].getOrthogonalValue( ) ) )
			{
				// Skip the invalid entry
				continue;
			}

			// always add negative point in the bottom, positive point
			// in the top
			nStart.addToListBottom( points );
			pStart.addToList( points );

			pEnd = new CPoint( loaP[i].getX( ), loaP[i].getY( ), isTransposed );
			nEnd = new CPoint( loaN[i].getX( ), loaN[i].getY( ), isTransposed );

			CLine lp = new CLine( pStart, pEnd );
			CLine ln = new CLine( nStart, nEnd );

			// Render two lines
			renderLine( lp, lre, dc, liaP );
			renderLine( ln, lre, dc, liaN );

			// To find the intersection of two lines
			CPoint intersection = lp.findIntersection( ln );

			// If no intersection or the point may be counted in before
			if ( intersection != null
					&& !intersection.equals( lp.start )
					&& !intersection.equals( ln.start ) )
			{
				intersection.addToList( points );
				if ( points.size( ) > 1 )
				{
					renderPolygon( points.getPoints( ),
							pre,
							ipr,
							pStart.compareY( nStart ) >= 0 ? fillColorP
									: fillColorN,
							renderer.getSeries( ) );

					// Start the next polygon
					points.clear( );
					intersection.addToList( points );
				}
			}

			// Since it's the last point, no need to find the intersection
			if ( i == lindex || i == dpha.length - 1 )
			{
				nEnd.addToListBottom( points );
				pEnd.addToList( points );
				if ( points.size( ) > 1 && !locationEquals( loaP, loaN ) )
				{
					renderPolygon( points.getPoints( ),
							pre,
							ipr,
							pEnd.compareY( nEnd ) >= 0 ? fillColorP
									: fillColorN,
							renderer.getSeries( ) );
				}
				points.clear( );
				break;
			}

			pStart = pEnd;
			nStart = nEnd;
		}

	}

	static void renderPolygon( List<CPoint> points, PolygonRenderEvent pre,
			IPrimitiveRenderer ipr, Fill fillColor, Series as )
			throws ChartException
	{
		Location[] pa = new Location[points.size( )];
		Iterator<CPoint> it = points.iterator( );
		for ( int i = 0; it.hasNext( ); i++ )
		{
			pa[i] = it.next( ).toLocation( );
		}
		pre.setOutline( null );
		pre.setPoints( pa );
		pre.setBackground( fillColor );
		pre.setSourceObject( StructureSource.createSeries( as ) );
		ipr.fillPolygon( pre );
	}

	static void renderLine( CLine line, LineRenderEvent lre, DeferredCache dc,
			LineAttributes lia ) throws ChartException
	{
		if ( lia.isVisible( ) )
		{
			lre.setStart( line.start.toLocation( ) );
			lre.setEnd( line.end.toLocation( ) );
			lre.setLineAttributes( lia );
			// Use deferred cache to ensure Line rendering above polygon
			dc.addLine( lre );
		}
	}

	static Fill getSeriesPaletteEntry( AxesRenderer renderer )
	{
		Fill fPaletteEntry = null;
		SeriesDefinition sd = null;

		Series se = renderer.getSeries( );

		if ( se.eContainer( ) instanceof SeriesDefinition )
		{
			sd = (SeriesDefinition) se.eContainer( );
		}

		if ( sd != null )
		{
			int iThisSeriesIndex = sd.getRunTimeSeries( ).indexOf( se );
			if ( iThisSeriesIndex >= 0 )
			{
				EList<Fill> ePalette = sd.getSeriesPalette( ).getEntries( );
				fPaletteEntry = FillUtil.getPaletteFill( ePalette,
						iThisSeriesIndex );

				renderer.updateTranslucency( fPaletteEntry, se );
			}
		}

		return fPaletteEntry;
	}

	public static boolean isValidDifferenceEntry( Object obj )
	{
		if ( obj instanceof DifferenceEntry )
		{
			DifferenceEntry entry = (DifferenceEntry) obj;
			if ( !Double.isNaN( entry.getPositiveValue( ) )
					&& !Double.isNaN( entry.getNegativeValue( ) ) )
			{
				return true;
			}
		}
		return false;
	}

	/**
	 * Return the index of first non-null value.
	 * 
	 * @param dpha
	 */
	static int getFirstNonNullIndex( DataPointHints[] dpha )
	{
		for ( int i = 0; i < dpha.length; i++ )
		{
			if ( isValidDifferenceEntry( dpha[i].getOrthogonalValue( ) ) )
			{
				return i;
			}
		}
		return -1;
	}

	/**
	 * Returns the index of last non-null value.
	 * 
	 * @param dpha
	 */
	static int getLastNonNullIndex( DataPointHints[] dpha )
	{
		for ( int i = dpha.length - 1; i >= 0; i-- )
		{
			if ( isValidDifferenceEntry( dpha[i].getOrthogonalValue( ) ) )
			{
				return i;
			}
		}
		return -1;
	}

	public static void renderDifferenceCurve( AxesRenderer renderer,
			IPrimitiveRenderer ipr, DataPointHints[] dpha, Location[] loaP,
			Location[] loaN, LineAttributes liaP, LineAttributes liaN,
			Fill paletteEntry ) throws ChartException
	{
		CPoint.bPrecise = true;

		boolean bConnectingMissing = ( (LineSeries) renderer.getSeries( ) ).isConnectMissingValue( );
		List listP = CurveRenderer.generateCurvePoints( renderer,
				loaP,
				bConnectingMissing,
				0,
				0 );
		List listN = CurveRenderer.generateCurvePoints( renderer,
				loaN,
				bConnectingMissing,
				0,
				0 );

		if ( listP == null
				|| listN == null || listP.size( ) < 2 || listN.size( ) < 2 )
		{
			return;
		}
		final int lengthP = listP.size( );
		final int lengthN = listN.size( );

		final boolean bTransposed = ( (ChartWithAxes) renderer.getModel( ) ).isTransposed( );
		final LineRenderEvent lre = ( (EventObjectCache) ipr ).getEventObject( StructureSource.createSeries( renderer.getSeries( ) ),
				LineRenderEvent.class );
		final PolygonRenderEvent pre = ( (EventObjectCache) ipr ).getEventObject( StructureSource.createSeries( renderer.getSeries( ) ),
				PolygonRenderEvent.class );
		final DeferredCache dc = renderer.getDeferredCache( );

		final Fill[] fills = createUpdateFills( renderer, paletteEntry );
		final Fill fillColorP = fills[0];
		final Fill fillColorN = fills[1];

		// Points to render polygon
		CPointContainer points = new CPointContainer( );

		CPoint pStart = new CPoint( (double[]) listP.get( 0 ),
				kError,
				bTransposed );
		CPoint nStart = new CPoint( (double[]) listN.get( 0 ),
				kError,
				bTransposed );
		CPoint pEnd, nEnd;
		int i = 1;
		int j = 1;
		// Since the NaN points have been filtered out during Curve generation,
		// no need more null check in loop
		while ( i < lengthP && j < lengthN )
		{
			pEnd = new CPoint( (double[]) listP.get( i ), kError, bTransposed );
			nEnd = new CPoint( (double[]) listN.get( j ), kError, bTransposed );
			final CLine lineP = new CLine( pStart, pEnd );
			final CLine lineN = new CLine( nStart, nEnd );

			if ( nStart.compareX( pEnd ) >= 0 || lineP.isVertical( ) )
			{
				// Use next positive line
				i++;
				pStart = pEnd;

				lineP.start.addToList( points );
				renderLine( lineP, lre, dc, liaP );
				continue;
			}
			else if ( pStart.compareX( nEnd ) >= 0 || lineN.isVertical( ) )
			{
				// Use next negative line
				j++;
				nStart = nEnd;

				lineN.start.addToListBottom( points );
				renderLine( lineN, lre, dc, liaN );
				continue;
			}

			CPoint intersection = lineP.findIntersection( lineN );

			// If no intersection or the point may be counted in before
			if ( intersection == null
			// || intersection.equals( lineP.start )
			// || intersection.equals( lineN.start )
			)
			{
				// always add negative point in the bottom, positive point
				// in the top
				lineN.start.addToListBottom( points );
				lineP.start.addToList( points );
			}
			else
			{
				intersection.addToList( points );
				// pIndex++;
				renderPolygon( points.getPoints( ),
						pre,
						ipr,
						pStart.compareY( nStart ) >= 0 ? fillColorP
								: fillColorN,
						renderer.getSeries( ) );

				// Start the next polygon
				points.clear( );
				intersection.addToList( points );
			}

			i++;
			j++;
			renderLine( lineP, lre, dc, liaP );
			renderLine( lineN, lre, dc, liaN );
			pStart = pEnd;
			nStart = nEnd;
		}

		while ( i <= lengthP )
		{
			pEnd = new CPoint( (double[]) listP.get( i - 1 ),
					kError,
					bTransposed );
			pEnd.addToList( points );
			renderLine( new CLine( pStart, pEnd ), lre, dc, liaP );
			i++;
			pStart = pEnd;
		}
		while ( j <= lengthN )
		{
			nEnd = new CPoint( (double[]) listN.get( j - 1 ),
					kError,
					bTransposed );
			nEnd.addToListBottom( points );
			renderLine( new CLine( nStart, nEnd ), lre, dc, liaN );
			j++;
			nStart = nEnd;
		}

		if ( points.size( ) > 2 )
		{
			// Fix Bugzilla bug 188846.
			if ( !locationEquals( loaP, loaN ) )
			{
				renderPolygon( points.getPoints( ),
						pre,
						ipr,
						pStart.compareY( nStart ) >= 0 ? fillColorP
								: fillColorN,
						renderer.getSeries( ) );
			}
			points.clear( );
		}
	}

	/**
	 * Check if specified locations are equal.
	 * 
	 * @param loaP
	 *            specified location array.
	 * @param loaN
	 *            specified location array.
	 * @return <code>true</code> if specified location arrays are equal, then
	 *         <code>false</code>.
	 */
	private static boolean locationEquals( Location[] loaP, Location[] loaN )
	{
		if ( loaP.length != loaN.length )
		{
			return false;
		}

		for ( int i = 0; i < loaP.length; i++ )
		{
			if ( loaP[i].getX( ) != loaN[i].getX( )
					|| loaP[i].getY( ) != loaN[i].getY( ) )
			{
				return false;
			}
		}

		return true;
	}
}
